TPWS

[Buff69]

Hi all, so it looks like we have a slow leak in a rear tyre and have to go and get it checked out, as we have the TPWS is there any considerations? ie make sure the guy knows so he/she doesn’t break anything on the wheel?,  is there any recalibration to be done at Toyota?. Many thanks 

[philip42h]

Assuming that the TPWS on a 4.5 is broadly the same as the TPMS fitted to my 4.4 (and 4.3) then there's not too much to worry about.

Clearly if the slow leak is a result of a fault in the valve you would need the valve replaced (which will be relatively expensive) and the new valve would need to be coded into the system by Mr T.

Otherwise, if it is a slow puncture it can be fixed in the traditional manner - no real issues there.

If the tyre does have to come off the rim to be reseated / replaced, care must be taken not to damage the TPMS valve in the process but tyre fitters have been working with these valves for quite a while now so you'd be really unlucky to come across one who doesn't know the drill by now.

Assuming that the valve doesn't need to be replaced, no 'recalibration' will be required - the car will already be set to recognise the correct pressures. On previous models, so I assume the 4.5 will be the same, there is an owner accessible feature to reset the warning system. This involves setting all four tyres to the correct pressures and "pressing a button" to tell the system that the pressures are correctly set. So, you could read the manual to find that function on the 4.5 but you really won't need to! 😉

[Buff69]

Cheers philip42h sorry I wrote the wrong initials it’s not TPWS (as on the railway tracks) but TPMS oops 😬 thanks for the info 👍

[flash22]

The sensors self calibrate, the Battery in the valve can fail but most decent tire places have a reader

[philip42h]

50 minutes ago, Buff69 said:

Cheers philip42h sorry I wrote the wrong initials it’s not TPWS (as on the railway tracks) but TPMS oops 😬 thanks for the info 👍

No, you didn't get it wrong - Toyota do now refer to a Tyre Pressure Warning System (TPWS) on the RAV4.5 ... 😄

[PeteB]

There are 2 systems:

1. The basic one, like fitted to most Toyotas is TPWS - Tyre Pressure Warning System - it tells you a tyres is losing pressure, but not which one.
    
2. The better system, fitted to some Lexus and other upmarket cars is TPMS - the M standing for Monitoring.  These display a map of the car's wheels with actual pressures, sometimes temperatures as well.

[FROSTYBALLS]

There is actually a third system (indirect), which uses the ABS sensors to detect rotational differences between the wheels. 

Fitted as standard to the second generation Aygo.

[Buff69]

Update, just had Kwikfit mobile fitter change the tyre as the “screw” in the tyre was just borderline on fixing,as the patch would have been on the sidewall a bit. Took all of ten minutes and he used an airbag as a jack very cool, he put a Bridgestone on so don’t know what they are like. just have to see if the TPWS has been affected but I don’t think I’ll need to do anything. Good luck all and stay safe 👍

[Thermal]

If I remember correctly, it is like PeteB wrote: you'll get a warning but no indication as to what tyre it is. I had a TPWS warning last september, and I checked all 4.
One tyre pressure was 0.2 bar lower than the others, so I made them all equal (2.5 bar). However, the warning did not go away for another 2 days, so I looked it up in the manual. There is a menu item where you can set the pressures. As in "OK RAV4, I corrected your pressures and they are now correct. <Enter>".

Now the warning went away and to my surpise, the screen showed the pressures in all 4 tyres! So the system knows what the current pressures are, but keeps you in the dark when the warning pops up. Nice 😒